1. Field of the Invention
The invention relates to structural support for elongated tubes, or pipes, mounted on the refractory of furnace walls with replaceable parts. More specifically, the invention relates to a multi-part hanger which supports a furnace tube within a furnace space and which includes a part most vulnerable to service conditions but which is readily replaced.
2. Description of the Prior Art
The high temperatures and wide swings in temperature within an industrial furnace are factors in creating a severely hostile environment for any structures within the furnace. Of course the central structure is the tube, or pipe, carrying the fluid to be heated. It is common practice to support these conduits at the walls of the furnace so they will be exposed to the heat of combustion within the furnace.
It is common practice to line the internal wall of the furnace with four to six inches of refractory and suspend the pipes at the surface of this material. Positions are selected along the interior shell of the furnace for supports to be welded to the metallic wall and extended above the refractory and about the tubes for their support.
Of course the more simple form for the hanger, or strap, the less expense in the original installation. However, the need for repair and replacement is always hovering in the background. If a strap crumbles under the furnace conditions, or its tube fails, whatever remains of the strap must be removed and replaced.
Remember, the strap or hanger is simple in form but it extends from the wall of the shell. To get at its connection to the wall, refractory must be removed at its location. If the strap is intact, but the tube has ruptured, the tube must be withdrawn from the strap or the strap must be cut to remove the tube. Strap or tube failure, the prior art practice always includes a messy repair and replacement program.
In design of all furnace parts exposed to the heat generated at the burner, the parts are thought of as "consumed." There is a deterioration of materials in the furnace which are exposed to temperature ranges including 1400.degree. F. and the products of combustion. This progressive wasting away is understandably termed consumption. This factor is of prime importance to the engineer of furnace parts.
In the tube support there are certain parts which are unavoidably exposed to the full force of the furnace conditions. The problem is to provide a support whose more consumable part, or parts, can be readily replaced and to keep their exposed surface to a mimimum.